The symbol used to denote an integral . The symbol was invented by Leibniz and chosen to be a stylized script "S" to stand for "summation."
Integral Sign
See also
Integral, Integration Under the Integral SignExplore with Wolfram|Alpha
Cite this as:
Weisstein, Eric W. "Integral Sign." From MathWorld--A Wolfram Web Resource. https://mathworld.wolfram.com/IntegralSign.html